CN1791784B

CN1791784B - Solid-state laser gyroscope stabilized by an acousto-optic setup

Info

Publication number: CN1791784B
Application number: CN200480013431.6A
Authority: CN
Inventors: G·皮格奈特; D·罗利; J-P·波楚利
Original assignee: Thales SA
Current assignee: Thales SA
Priority date: 2003-05-16
Filing date: 2004-04-28
Publication date: 2010-08-18
Anticipated expiration: 2024-04-28
Also published as: RU2350904C2; CN1791784A; FR2854947A1; WO2004102120A1; RU2005139157A; JP2007505325A; EP1625353A1; US7446879B2; US20060285118A1; FR2854947B1

Abstract

The invention relates to solid state gyrolasers. A major problem inherent with said technique is that the optical cavity of this type of laser is by nature very unstable. According to the invention, said instability may be reduced by introduction into said cavity (1) of controlled optical losses, depending on the sense of propagation, by means of acousto-optical devices. Several devices are disclosed, using different configurations of acousto-optical devices. Said devices are particularly of application to lasers with monolithic cavities and, in particular, to lasers of the neodymium-YAG type.

Description

Solid-state laser gyroscope stabilized by an acousto-optic setup

技术领域technical field

本发明的领域是用于对转动速度进行测量的固态激光陀螺仪的领域。这种类型的装置被特别用于航空应用。The field of the invention is that of solid-state laser gyroscopes for the measurement of rotational speed. Devices of this type are used in particular for aeronautical applications.

背景技术Background technique

三十多年前被开发出的固态激光陀螺仪目前得到广泛、大规模地使用。其工作原理是基于萨格奈克效应(Sagnac effect)，其包括被称为逆向传播模式的在经历转动的双向激光环形腔(bidirectional laserring cavity)的相反方向上传播的两个光学传输模式之间的频率差Δv。通常，该频率差Δv等于：Solid-state laser gyroscopes, which were developed more than thirty years ago, are now widely used on a large scale. Its working principle is based on the Sagnac effect, which consists of a so-called counter-propagating mode between two optical transmission modes propagating in opposite directions of a bidirectional laser ring cavity undergoing rotation. The frequency difference Δv. Typically, this frequency difference Δv is equal to:

Δv＝4AΩ/λLΔv＝4AΩ/λL

其中：L和A分别是光学环形腔体的长度和面积；λ是不把萨格奈克效应包括在内的激光发射波长；以及，Ω是组件的转动速度。Where: L and A are the length and area of the optical ring cavity, respectively; λ is the laser emission wavelength not including the Sagnac effect; and, Ω is the rotation speed of the component.

通过两束被发射光束的拍频(beat)的频谱分析进行测量的Δv的值被用于对Ω的值进行非常精确地确定。The value of Δv, measured by spectral analysis of the beat frequencies of the two emitted beams, is used to determine the value of Ω very precisely.

此外，还已经表明，激光陀螺仪只有在高于一定的转动速度时才能正确地工作，该转动速度被需要用于减少相互耦合(intermodalcoupling)的影响。比此界限低的转动速度范围通常被称为盲区。Furthermore, it has also been shown that laser gyroscopes only work correctly above a certain rotational speed, which is required to reduce the influence of intermodal coupling. The range of rotational speeds below this limit is often referred to as the dead zone.

用于观察拍频、并因此用于激光陀螺仪的工作的条件是在两个方向上所发射的强度的稳定性和相对的相等性。由于相互竞争(intermodalcompetition)现象，这不是一件容易达到的事情，该现象意味着两个逆向传播的光学模式之一可能具有独占可利用的增益(gain)的趋势，导致损害另一模式。A condition for observing the beat frequency, and thus for the operation of the laser gyroscope, is the stability and the relative equality of the emitted intensities in both directions. This is not an easy thing to achieve due to the phenomenon of intermodal competition, which means that one of the two counter-propagating optical modes may have a tendency to monopolize the available gain, leading to the detriment of the other mode.

通过通常工作在室温下的氦/氖混合物的气体放大媒介(medium)的使用，这个问题在标准的激光陀螺仪中得到解决。由于原子的热激发(thermal agitation)，气体混合物的增益腔呈现多普勒加宽(Dopplerbroadening)。因此，能够把增益传递给给定的频率模式的原子只是那些其速度包括在跃迁频率(transition frequency)中的多普勒移动(Doppler shift)的原子，该跃迁频率使原子与正在讨论的模式发生共振。促使激光发射不发生在增益腔的中心(通过对光路长度进行压电调节)保证了与光学环形腔体发生共振的原子具有非零速度。因此，在一个或两个方向上能够对增益作出贡献的原子与那些在相反的方向上能够对增益作出贡献的原子具有相反的速度。因此，该系统如同具有两个独立的放大媒介那样工作，每个放大媒介用于一个方向。由于相互竞争已经因此消失，所以，产生了稳定和平衡的双向发射(特别是，为了减轻其他问题，包括两种不同的氖同位素的混合物被使用)。This problem is solved in standard laser gyroscopes by the use of a gas amplifying medium of a helium/neon mixture, usually operating at room temperature. The gain cavity of the gas mixture exhibits Doppler broadening due to thermal agitation of the atoms. Thus, the atoms that are able to impart gain to a given frequency mode are only those whose velocities include a Doppler shift in the transition frequency that brings the atom into alignment with the mode in question resonance. Facilitating lasing not to occur at the center of the gain cavity (via piezoelectric tuning of the optical path length) ensures that the atoms resonating with the optical ring cavity have non-zero velocities. Thus, atoms that can contribute to gain in one or both directions have opposite velocities to those atoms that can contribute to gain in the opposite direction. Thus, the system works as if it had two independent magnification media, one for each direction. Since the mutual competition has thus disappeared, a stable and balanced bi-directional emission is produced (in particular, to alleviate other problems, a mixture involving two different neon isotopes is used).

不过，放大媒介的气体性质(gaseous nature)是生产激光陀螺仪时技术复杂的根源(尤其是因为所需要的高的气体纯度)，以及在使用期间过早损耗的根源(气体泄露，电极的损坏，用于建立粒子数反转的高电压，等。)。However, the gaseous nature of the amplifying medium is a source of technical complexity when producing laser gyroscopes (especially because of the high gas purity required), as well as premature wear during use (gas leaks, damage to electrodes , high voltage for establishing population inversion, etc.).

目前，有可能使用例如基于掺杂钕的YAG(钇铝石榴石)晶体而不是氦/氖气体混合物的放大媒介，生产出工作在可视或近红外中的固态激光陀螺仪，于是，光学泵浦通过工作在近红外中的激光二极管被提供。还有可能把半导体材料、晶体基体(matrix)或掺杂有属于稀土类(铒、镱等)的离子的玻璃用作放大媒介。因此，放大媒介的气体状态所固有的所有问题被实际消除。不过，由于包括非常强的相互竞争的固态媒介的增益腔的加宽(broadening)具有均匀特性(homogeneous character)，以及，由于存在大量不同的工作状态，其中，被称为“拍频状态(beat regime)”的强度-平衡的双向状态是一种非常不稳定的特殊情况，所以这种结构很难被制造出(N.Kravtsov andE.Lariotsev，“Self-modulation oscillations and relaxations processes insolid-state ring lasers”，Quantum Electronics 24(10)，841-856(1994))。这个主要的物理上的障碍已经大大限制了迄今为止的固态激光陀螺仪的发展。Currently, it is possible to produce solid-state laser gyroscopes operating in the visible or near-infrared using, for example, amplification media based on neodymium-doped YAG (yttrium-aluminum-garnet) crystals instead of helium/neon gas mixtures, thus, optically pumped The pump is provided by a laser diode operating in the near infrared. It is also possible to use semiconductor materials, crystal matrices or glasses doped with ions belonging to the rare earths (erbium, ytterbium, etc.) as amplification medium. Thus, all problems inherent in the gaseous state of the amplifying medium are virtually eliminated. However, due to the homogeneous character of the broadening of the gain cavity including very strongly competing solid-state media, and due to the existence of a large number of different operating states, which are referred to as "beat states"regime)" strength-equilibrium bidirectional state is a very unstable special case, so this structure is difficult to be fabricated (N.Kravtsov andE.Lariotsev, "Self-modulation oscillations and relaxations processes insolid-state ring lasers ", Quantum Electronics 24 (10), 841-856 (1994)). This major physical obstacle has greatly limited the development of solid-state laser gyroscopes to date.

为了减轻这个缺点，一种技术解决方案包括根据光学模式的传播方向及其强度，通过在光学环形腔体中引入光的损耗，而在固态环形激光器中削弱逆向传播模式之间的竞争效果。其原理是根据两个传输模式之间强度的不同，通过反馈装置对这些损耗进行调节，以便对较弱的模式进行支持，同时削弱另一个模式，从而不断地对两个逆向传播的光学模式的强度进行自动控制，使达到相同的值。To alleviate this drawback, one technical solution consists in weakening the competing effect between counterpropagating modes in solid-state ring lasers by introducing losses of light in the optical ring cavity, depending on the direction of propagation of the optical mode and its intensity. The principle is that these losses are adjusted by a feedback device according to the difference in intensity between the two transmitted modes, so that the weaker mode is supported while the other mode is weakened, thereby continuously compensating for the two counter-propagating optical modes. The intensity is automatically controlled so that the same value is achieved.

在1984年，一种反馈装置被提出，其中，损耗借助于一种光学组件而被获得，该光学组件必须包括呈现多种法拉第效应的元件和偏振元件(A.V.Dotsenko and E.G.Lariontsev，“Use of a feedback circuit for theimprovement of the characteristics of a solid-state ring laser”，SovietJournal of Quantum Electronics 14(1)，117-118(1984)and A.V.Dotsenko，L.S.Komienko，N.V.Kravtsov，E.G.Lariontsev，O.E.Nanii and A.N.Shelaev，“Use of a feedback loop for the stabilization of a beat regime in asolid-state ring laser”，Soviet Journal of Quantum Electronics 16(1)，58-63(1986))。In 1984, a feedback device was proposed in which the losses were obtained by means of an optical assembly that had to include elements exhibiting various Faraday effects and polarizing elements (AVDotsenko and EGLariontsev, “Use of a feedback circuit for the improvement of the characteristics of a solid-state ring laser", SovietJournal of Quantum Electronics 14 (1), 117-118(1984) and AVDotsenko, LS Komienko, NVKravtsov, EGLariontsev, OENanii and ANShelaev, "Use of a feedback loop for the stabilization of a beat regime in a solid-state ring laser”, Soviet Journal of Quantum Electronics 16 (1), 58-63 (1986)).

这种反馈装置的原理在图1中被示出。其包括引入到光学环形腔体1中的包括三个反射镜11、12、13和固态放大媒介19，安置在逆向传播光学模式5和逆向传播光学模式6的通路上的光学组件，所述组件包括偏振元件7和缠有感应线圈73、呈现法拉第效应的光学导杆(optical pad)72。在光学环形腔体1的输出处，两个光学模式5和6被送到用于测量的光电二极管3。光束5和光束6的一部分借助两个半反射板43被分开，并被送到两个光电检测器42。由这两个光电检测器输出的信号代表了这两个逆向传播的光学模式5和6的光强。所述信号被送到电反馈模块4，其产生与两个光学模式之间的光强差成比例的电流。此电流对在每个逆向传播的模式5和6处所经受的损耗的值进行确定。如果一束光比另一束光具有较高的光强，其强度将被更多地减弱，从而使输出光束具有相同的强度水平。因此，双向状态是强度稳定的。The principle of such a feedback device is shown in FIG. 1 . It comprises an optical assembly introduced into an optical annular cavity 1 comprising three mirrors 11, 12, 13 and a solid-state amplifying medium 19, placed on the path of the counter-propagating optical mode 5 and the counter-propagating optical mode 6, said assembly It includes a polarizing element 7 and an optical pad 72 wrapped with an induction coil 73 and exhibiting the Faraday effect. At the output of the optical ring cavity 1 the two optical modes 5 and 6 are sent to a photodiode 3 for measurement. The light beam 5 and part of the light beam 6 are separated by means of two semi-reflective plates 43 and sent to two photodetectors 42 . The signals output by the two photodetectors represent the light intensities of the two counterpropagating optical modes 5 and 6 . The signal is sent to an electrical feedback module 4, which generates a current proportional to the difference in light intensity between the two optical modes. This current determines the value of the losses experienced at each counterpropagating mode 5 and 6. If one beam has a higher intensity than the other, its intensity will be attenuated more so that the output beams have the same intensity level. Therefore, the bidirectional state is intensity stable.

只有当反馈装置的参数与系统的动力学相匹配时，固态激光陀螺仪才能够根据该原理进行工作。为了反馈装置能够给出正确的结果，必须满足三个条件：Solid-state laser gyroscopes can only work according to this principle if the parameters of the feedback device are matched to the dynamics of the system. In order for a feedback device to give correct results, three conditions must be met:

·通过反馈装置引入到光学环形腔体内的额外的损耗必须与光学环形腔体内的固有损耗具有相同阶的量级；The additional loss introduced into the optical ring cavity by the feedback device must be of the same order as the inherent loss in the optical ring cavity;

·反馈装置的反应速度必须比被发射的模式的强度的变化速度更快，从而使反馈工作得令人满意；以及the feedback device must react faster than the intensity of the emitted pattern changes for the feedback to work satisfactorily; and

·最后，反馈装置的反馈强度对于在光学环形腔体中所引起的效果必须是足够的，以便对强度变化进行有效地补偿。• Finally, the feedback strength of the feedback means must be sufficient for the effect induced in the optical annular cavity in order to effectively compensate for intensity variations.

麦克斯韦方程被用于对逆向传播的光学模式的区域的复数幅度E_1，2、以及粒子数反转密度N进行确定。这些可以使用半常规(semi-conventional)模式而获得(N.Kravtsov and E.Lariotsev，“Self-modulation oscillations and relaxations processes in solid-state ringlasers”，Quantum Electronics 24(10)，841-856(1994))。Maxwell's equations are used to determine the complex amplitude E _1,2 of the region of the counter-propagating optical mode, and the population inversion density N. These can be obtained using a semi-conventional model (N. Kravtsov and E. Lariotsev, "Self-modulation oscillations and relaxations processes in solid-state ringlasers", Quantum Electronics 24 (10), 841-856 (1994) ).

这些方程是：These equations are:

方程1：dE_1，2/dt＝-(ω/2Q_1，2)E_1，2+i(m_1，2/2)E_2，1±i(Δv/2)E_1，2+(σ/2T)(E_1，2∫Ndx+E_2，1∫Ne^±2ikxdx)Equation 1: dE _1,2 /dt=-(ω/2Q _1,2 )E _1,2 +i(m _1,2 /2)E _2,1 ±i(Δv/2)E _1,2+ ( σ/2T)(E _1,2 ∫Ndx+E _2,1 ∫Ne ^±2ikx dx)

方程2：dN/dt＝W-(N/T₁)-(a/T₁)N|E₁e^-ikx+E₂e^ikx|² Equation 2: dN/dt=W-(N/T ₁ )-(a/T ₁ )N|E ₁ e ^-ikx +E ₂ e ^ikx | ²

其中：in:

系数1和2代表两个逆向传播的光学模式；Coefficients 1 and 2 represent two counterpropagating optical modes;

ω是不把萨格奈克效应包括在内的激光发射频率；ω is the laser emission frequency not including the Sagnac effect;

Q_1，2是在两个传播方向上光学环形腔体的品质因素；Q _{1, 2} is the quality factor of the optical ring cavity in both directions of propagation;

m_1，2是在两个传播方向上光学环形腔体的反向散射系数；m _1,2 is the backscattering coefficient of the optical ring cavity in both directions of propagation;

σ是有效的激光发射横截面；σ is the effective laser emission cross-section;

l是传播的增益媒介的长度；l is the length of the propagated gain medium;

T＝L/C是光学环形腔体的每个模式的传输时间；T=L/C is the transmission time of each mode of the optical ring cavity;

k＝2π/λ是波矢量的范数；k=2π/λ is the norm of the wave vector;

W是泵浦速度；W is the pump speed;

T₁是激发水平(excited level)的寿命；以及T ₁ is the lifetime of the excited level; and

a是饱和参数，其等于σT₁/8πhω。a is a saturation parameter, which is equal to σT ₁ /8πhω.

方程1的右边具有四项。第一项对应于由于光学环形腔体内的损耗而导致的区域中的变化，第二项对当光学环形腔体内存在散射元素时，通过一个模式在另一个模式上的反向散射而导致的区域中的变化，第三项对应于由于萨格奈克效应而导致的区域中的变化，以及，第四项对应于由于固态放大媒介的存在而导致的区域中的变化。第四项具有两个组成部分，第一部分对应于受激发射，以及，第二部分对应于当固态放大媒介内存在粒子数反转光栅(grating)时，一个模式在另一个模式上的反向散射。The right side of Equation 1 has four terms. The first term corresponds to the change in area due to losses inside the optical toroidal cavity and the second term to the area due to the backscattering of one mode on the other when a scattering element is present in the optical toroidal cavity The third term corresponds to the change in area due to the Sagnac effect, and the fourth term corresponds to the change in area due to the presence of the solid-state amplifying medium. The fourth term has two components, the first corresponding to stimulated emission, and the second corresponding to the inversion of one mode over the other when a population inversion grating is present within the solid-state amplification medium scattering.

方程2的右边具有三项，第一项对应于由于光学泵浦而导致的粒子数反转密度的变化，第二项对应于由于受激发射而导致的粒子数反转密度的变化，以及，第三项对应于由于自然发射而导致的粒子数反转密度的变化。The right-hand side of Equation 2 has three terms, the first term corresponds to the change in population inversion density due to optical pumping, the second term corresponds to the change in population inversion density due to stimulated emission, and, The third term corresponds to the change in population inversion density due to natural emission.

因此，根据方程1右边的第一项，在光学模式的完全转动(completerotation)之后，由于光学环形腔体而导致的平均损耗P_C因此是：Thus, according to the first term on the right hand side of Equation 1, after a complete rotation of the optical mode, the average loss _PC due to the optical ring cavity is thus:

p_C＝ωT/2Q_1，2 p _C =ωT/2Q _1,2

通过反馈装置P_F被引入的损耗与这些平均损耗P_C必须具有相同阶的量级。通常，这些损耗具有百分之一的阶。The losses introduced by the feedback means _PF must be of the same order as these average losses P _C . Typically, these losses are of the order of one hundredth.

反馈装置的反应速度可以由所述反馈装置的带宽γ进行表征。已经表明(A.V.Dotsenko and E.G.Lariontsev，“Use of a feedback circuit forthe improvement of the characteristics of a solid-state ring laser”，SovietJournal of Quantum Electronics 14(1)，117-118(1984)and A.V.Dotsenko，L.S.Komienko，N.V，Kravtsov，E.G.Lariontsev，O.E.Nanii and A.N.Shelaev，“Use of a feedback loop for the stabilization of a beat regime in asolid-state ring laser”，Soviet Journal of Quantum Electronics 16(1)，58-63(1986))，利用方程1和方程2，用于建立高于转动速度的稳定的双向状态的充分条件能够被写成：The reaction speed of the feedback device can be characterized by the bandwidth γ of the feedback device. It has been shown (AVDotsenko and EGLariontsev, "Use of a feedback circuit for the improvement of the characteristics of a solid-state ring laser", SovietJournal of Quantum Electronics 14 (1), 117-118 (1984) and AVDotsenko, LS Komienko, NV, Kravtsov , EGLariontsev, OENanii and ANShelaev, "Use of a feedback loop for the stabilization of a beat regime in a solid-state ring laser", Soviet Journal of Quantum Electronics 16 (1), 58-63(1986)), using equation 1 and Equation 2, the sufficient condition for establishing a stable bidirectional state above the rotational speed can be written as:

γ＞＞ηω/[Q_1，2(ΔvT₁)²]γ>>ηω/[Q _1,2 (ΔvT ₁ ) ² ]

其中η＝(W-W_threshold)/W和η对应于高于阀值W_threshold的相对泵浦速度。where η=(WW _threshold )/W and η corresponds to a relative pumping speed above the threshold _Wthreshold .

给出一个例子，对于相对的泵浦速度η为10％，光学频率ω为18×10¹⁴，品质因素Q_1，2为10⁷，频率差Δv为15kHz，以及，激发状态寿命T₁为0.2ms，带宽γ必须大于40kHz。To give an example, for a relative pumping speed η of 10%, an optical frequency ω of 18×10 ¹⁴ , a quality factor Q _1,2 of 10 ⁷ , a frequency difference Δv of 15 kHz, and an excited state lifetime T ₁ of 0.2 ms, bandwidth γ must be greater than 40kHz.

为了通路正确地进行工作，下面的关系也必须被满足：In order for the path to work correctly, the following relationship must also be satisfied:

(ΔvT₁)²＞＞1(ΔvT ₁ ) ² ＞＞1

通常，反馈装置的反馈强度q用下面的方式进行定义：Usually, the feedback strength q of the feedback device is defined in the following way:

q＝[(Q₁-Q₂)/(Q₁+Q₂)]/[(I₂-I₁)/(I₂+I₁)]q=[(Q ₁ -Q ₂ )/(Q ₁ +Q ₂ )]/[(I ₂ -I ₁ )/(I ₂ +I ₁ )]

其中，I₁和I₂是两个逆向传播的光学模式的光强。where _I1 and _I2 are the light intensities of the two counter-propagating optical modes.

在这种类型的应用中，已经显示出，为了反馈装置能够正确地工作，参数q必须大于1/(ΔvT₁)²。In this type of application, it has been shown that the parameter q must be greater than 1/(ΔvT ₁ ) ² for the feedback device to work correctly.

发明内容Contents of the invention

本发明的目的是提出一种用于固态激光陀螺仪的稳定装置，其包括用于利用光波在声波上的衍射现象、根据传播方向引入光学损耗的反馈系统。这种解决方案比现有技术的装置具有多种显著的优势。由于只有单一类型的组件被加入到光学环形腔体中，并且特殊的布置允许每个逆向传播模式的衰减被控制成几乎独立于另一个模式，所以易于实施。The object of the present invention is to propose a stabilization device for a solid-state laser gyroscope comprising a feedback system for introducing optical losses depending on the direction of propagation by exploiting the phenomenon of diffraction of light waves on acoustic waves. This solution has several significant advantages over prior art arrangements. It is easy to implement since only a single type of component is incorporated into the optical ring cavity, and a special arrangement allows the attenuation of each counter-propagating mode to be controlled almost independently of the other.

更确切的是，本发明的目的是一种激光陀螺仪，其至少包括包含至少三个反射镜的光学环形腔体，固态放大媒介和反馈系统，光学环形腔体和固态放大媒介使得两个逆向传播的光学模式能够在所述光学环形腔体中在相对于彼此的相反的方向上进行传播，反馈系统使两个逆向传播的光学模式的强度保持成几乎相同，其特征在于，反馈系统至少包括在光学环形腔体内的声光调制器，所述声光调制器包括至少一个被安置在逆向传播的光学模式的通路上的光学相互作用(interaction)媒介，以及在光学相互作用媒介中产生周期性声波的压电传感器。More precisely, the object of the present invention is a laser gyroscope comprising at least an optical ring cavity containing at least three mirrors, a solid-state amplification medium and a feedback system, the optical ring cavity and the solid-state amplification medium enable two reverse The propagating optical modes are capable of propagating in said optical annular cavity in opposite directions relative to each other, a feedback system keeps the intensities of the two counter-propagating optical modes nearly the same, characterized in that the feedback system comprises at least An acousto-optic modulator within an optical annular cavity, said acousto-optic modulator comprising at least one optical interaction medium disposed on the path of a counter-propagating optical mode, and generating periodicity in the optical interaction medium Piezoelectric sensors for acoustic waves.

附图说明Description of drawings

通过对下面以非限制性的例子的方式给出的描述以及通过对附图进行阅读，本发明将更好被理解，并且其他优势也将显而易见，其中：The invention will be better understood and other advantages will be apparent from the following description given by way of non-limiting example and from a reading of the accompanying drawings, in which:

图1示出了根据现有技术的反馈系统的工作原理；Figure 1 shows the working principle of a feedback system according to the prior art;

图2示出了通过声光调制器进行衍射的一般原理；Figure 2 shows the general principle of diffraction by an acousto-optic modulator;

图3a和3b示出了通过声光调制器在向前和向后的传播方向上被衍射的波的波矢量的结构；Figures 3a and 3b show the structure of wave vectors of waves diffracted by an acousto-optic modulator in the forward and backward directions of propagation;

图4a和4b示出了作为入射角的函数以及作为频率的函数的衍射效率；Figures 4a and 4b show diffraction efficiency as a function of angle of incidence and as a function of frequency;

图5对两个逆向传播的光学模式的衍射损耗进行比较；Figure 5 compares the diffraction losses of the two counterpropagating optical modes;

图6示出了根据本发明的激光陀螺仪的总图；Figure 6 shows a general diagram of a laser gyroscope according to the present invention;

图7a和7b示出了根据本发明的装置的第一个和第二个可选实施例，其包括两个声光调制器；Figures 7a and 7b show a first and a second alternative embodiment of a device according to the invention comprising two acousto-optic modulators;

图8示出了整块的激光光学环形腔体，其包括根据本发明的装置；以及Figure 8 shows a monolithic laser optics ring cavity including a device according to the invention; and

图9示出了现有装置的可选实施例。Figure 9 shows an alternative embodiment of an existing device.

具体实施方式Detailed ways

声光调制器2基本上包括被安置成紧靠相互作用媒介21的压电块22，相互作用媒介21对于光学辐射是可透过的，如图2所示。压电块产生能够对相互作用媒介的机械和光学性质进行改变的超声波。更确切地说，光学系数的周期性调制在媒介中被产生，因此，媒介可以如同光学衍射光栅那样工作。当光束F经过声光调制器2时，它的一部分能量通过衍射被损耗。当入射光束相对于声波具有被称为布拉格入射角的非常特殊的方向时，衍射光束D的能量处于最大值。这两个波之间的相互作用可通过光子和光子之间弹性的相互作用进行模拟。这种相互作用涉及能量的守恒和动量的守恒。The acousto-optic modulator 2 basically comprises a piezoelectric mass 22 arranged in close proximity to an interaction medium 21 which is transparent to optical radiation, as shown in FIG. 2 . The piezoelectric mass generates ultrasonic waves capable of altering the mechanical and optical properties of the interacting medium. More precisely, a periodic modulation of the optical coefficients is generated in the medium, so that the medium can behave like an optical diffraction grating. When the light beam F passes through the AOM 2, part of its energy is lost through diffraction. The energy of the diffracted beam D is at a maximum when the incident beam has a very specific orientation with respect to the acoustic wave known as the Bragg angle of incidence. The interaction between these two waves can be simulated by the elastic interaction between photons and photons. This interaction involves conservation of energy and conservation of momentum.

用于获得衍射光束的特性的通常的关系通常通过在用于动量守恒的方程中对衍射波相对于入射波的频率移动进行忽略而被建立。由于该问题具有对称性(symmetrical)，因此，根据光学模式的传播方向的损耗不能被严密地表示。The usual relationship for obtaining the properties of a diffracted beam is usually established by ignoring the frequency shift of the diffracted wave relative to the incident wave in the equation for the conservation of momentum. Since the problem is symmetrical, the loss according to the propagation direction of the optical mode cannot be strictly represented.

如果对这种移动进行考虑(R.Roy，P.A.Schulz and A.Walther，Opt.Lett.12，672(1987)and J.Neev and F.V.Kowalski，Opt.Lett.16，378(1991))，可以看到，用于两个逆向传播的光学模式的布拉格条件是不同的。换句话说，对于两个逆向传播的光学模式，衍射损耗是不同的。损耗中的这种差异较小，但是，它足以建立用于对逆向传播的光学模式进行控制的反馈系统。If this movement is considered (R. Roy, PASchulz and A. Walther, Opt. Lett. 12 , 672 (1987) and J. Neev and FV Kowalski, Opt. Lett. 16 , 378 (1991)), one can see , the Bragg conditions for the two counterpropagating optical modes are different. In other words, the diffraction losses are different for the two counterpropagating optical modes. This difference in loss is small, but it is sufficient to create a feedback system for controlling the counter-propagating optical modes.

光波通常由其波矢量k、其角频率ω以及其波长λ进行表征。A light wave is usually characterized by its wave vector k, its angular frequency ω, and its wavelength λ.

使入射光传播进入以任意方向为正方向的给定方向，其由波矢量

和波长λ_o进行表征，所述波具有对应于在光学系数为n的相互作用媒介上的布拉格入射的入射角θ_B ⁺，由波矢量

声波的传播速度V_S、波长λ_S和角频率ω_S进行表征的声波在相互作用媒介中传播。在相互作用媒介中，波因子的衍射波在方向θ_d ⁺上被构成，如图3a所示。因此，下面的方程可以被写为：Let the incident light propagate into a given direction with any direction as the positive direction, which is determined by the wave vector

and wavelength λ _o with an angle of incidence θ _B ⁺ corresponding to Bragg incidence on the interaction medium with optical coefficient n, given by the wave vector

Acoustic waves characterized by their propagation velocity V _S , wavelength λ _S and angular frequency ω _S propagate in the interacting medium. In an interacting medium, the wave factor The diffracted wave of is formed in the direction _θd ⁺ , as shown in Fig. 3a. Therefore, the following equation can be written as:

以及

其中

以及k_SV_S＝ω_Sc表示光速，k_i ⁺、k_d ⁺和k_S表示相关的波矢量的范数。

as well as

in

And k _S V _S = ω _S c represents the speed of light, _ki ⁺ , k _d ⁺ and k _S represent the norms of the associated wave vectors.

通过投影到与方向

垂直的O_X轴上，可以得到下面的方程：By projecting to and direction

On the vertical O _X axis, the following equation can be obtained:

$k_{i}^{+} \cos (θ_{B}^{+}) = k_{d}^{+} \cos (θ_{d}^{+})$ 方程1 $k_{i}^{+} \cos (θ_{B}^{+}) = k_{d}^{+} \cos (θ_{d}^{+})$ Equation 1

由于衍射波在与声波相互作用后频率被移动，所以k_i ⁺与k_d ⁺不同，并且因此，入射角θ_B ⁺与衍射角θ_d ⁺不同，如图3a所示，这里，为了简单起见，对这种差异进行了相当的夸大。Since the frequency of the diffracted wave is shifted after interacting with the acoustic wave, _ki ⁺ is different from _kd ⁺ , and therefore, the angle of incidence _θB ⁺ is different from the angle of diffraction _θd ⁺ , as shown in Fig. 3a, here, for simplicity , a considerable exaggeration of this difference.

通过投影到与

相平行的O_Y轴上，可以得到下面的方程：by projecting onto the

On the parallel O _Y axis, the following equation can be obtained:

$- k_{i}^{+} \sin (θ_{B}^{+}) = k_{d}^{+} \sin (θ_{d}^{+}) - k_{S}$ 方程2 $- k_{i}^{+} \sin (θ_{B}^{+}) = k_{d}^{+} \sin (θ_{d}^{+}) - k_{S}$ Equation 2

对方程1和方程2进行平方，得到：Squaring Equation 1 and Equation 2 gives:

${k k}_{i i}^{+ +}^{22} {cos cos}^{22} (({θ θ}_{B B}^{+ +})) = = {k k}_{d d}^{+ +}^{22} {cos cos}^{22} (({θ θ}_{d d}^{+ +}))$

${k k}_{i i}^{+ +}^{22} {sin sin}^{22} (({θ θ}_{B B}^{+ +})) + + {k k}_{S S}^{22} - - 22 {k k}_{i i}^{+ +} {k k}_{S S} {sin sin}^{22} (({θ θ}_{B B}^{+ +})) = = {k k}_{d d}^{+ +}^{22} {sin sin}^{22} (({θ θ}_{d d}^{+ +}))$

并且，接着把这两个方程相加，得到：And, then adding these two equations gives:

${k k}_{i i}^{+ +}^{22} + + {k k}_{S S}^{22} - - 22 {k k}_{i i}^{+ +} {k k}_{S S} sin sin (({θ θ}_{B B}^{+ +})) = = {k k}_{d d}^{+ +}^{22}$

${k k}_{i i}^{+ +}^{22} + + {k k}_{S S}^{22} - - {k k}_{d d}^{+ +}^{22} = = 22 {k k}_{i i}^{+ +} {k k}_{S S} sin sin (({θ θ}_{B B}^{+ +}))$

$22 {k k}_{i i}^{+ +} {k k}_{S S} sin sin (({θ θ}_{B B}^{+ +})) = = \frac{{k k}_{i i}^{+ +}^{22} - - {k k}_{d d}^{+ +}^{22}}{{k k}_{S S}} + + {k k}_{S S}$

对于在相反方向上传播的入射光，以任意方向为负方向(图3b)，通过其波矢量

及其波长λ_o进行表征，可以接着得到下面的方程：For incident light propagating in the opposite direction, taking any direction as the negative direction (Fig. 3b), through its wave vector

and its wavelength λ _o for characterization, the following equation can then be obtained:

以及

其中

以及k_SV_S＝ω_S as well as

in

and k _S V _S = ω _S

${k k}_{i i}^{- -} cos cos (({θ θ}_{B B}^{- -})) = = {k k}_{d d}^{- -} cos cos (({θ θ}_{d d}^{- -}))$

${k k}_{i i}^{- -} sin sin (({θ θ}_{B B}^{- -})) = = - - {k k}_{d d}^{- -} sin sin (({θ θ}_{d d}^{- -})) + + {k k}_{S S}$

使用如上的同样方法，可以接着得到下面的方程：Using the same method as above, the following equation can then be obtained:

${k k}_{i i}^{- -}^{22} {cos cos}^{22} (({θ θ}_{B B}^{- -})) = = {k k}_{d d}^{- -}^{22} {cos cos}^{22} (({θ θ}_{d d}^{- -}))$

${k k}_{i i}^{- -}^{22} {sin sin}^{22} (({θ θ}_{B B}^{- -})) + + {k k}_{S S}^{22} - - 22 {k k}_{i i}^{- -} {k k}_{S S} {sin sin}^{22} (({θ θ}_{B B}^{- -})) = = {k k}_{d d}^{- -}^{22} {sin sin}^{22} (({θ θ}_{d d}^{- -}))$

其给出了用于逆向传播的波的等价方程：which gives the equivalent equation for counterpropagating waves:

$22 {k k}_{i i}^{- -} sin sin (({θ θ}_{B B}^{- -})) = = \frac{{k k}_{i i}^{- -}^{22} - - {k k}_{d d}^{- -}^{22}}{{k k}_{S S}} + + {k k}_{S S}$

这两个方程还可以被写成下面的简化形式：These two equations can also be written in the following simplified form:

$22 {k k}_{i i}^{&PlusMinus; &PlusMinus;} sin sin (({θ θ}_{B B}^{&PlusMinus; &PlusMinus;})) = = {k k}_{S S} + + \frac{{k k}_{i i}^{&PlusMinus; &PlusMinus;}^{22} - - {k k}_{d d}^{&PlusMinus; &PlusMinus;}^{22}}{{k k}_{S S}}$

因此，布拉格入射角之间的差异给出为：Therefore, the difference between the Bragg incidence angles is given by:

$k_{i}^{+} \sin (θ_{B}^{+}) - k_{i}^{-} \sin (θ_{B}^{-}) = \frac{{k_{i}^{+}}^{2} - {k_{i}^{-}}^{2} + {k_{d}^{-}}^{2} - {k_{d}^{+}}^{2}}{2 k_{S}}$ 方程3 $k_{i}^{+} \sin (θ_{B}^{+}) - k_{i}^{-} \sin (θ_{B}^{-}) = \frac{{k_{i}^{+}}^{2} - {k_{i}^{-}}^{2} + {k_{d}^{-}}^{2} - {k_{d}^{+}}^{2}}{2 k_{S}}$ Equation 3

由于衍射波具有与入射波不同的频率，所以对于衍射为极大的两个方向不相同。因此，这里存在非互逆(nonreciprocal)的效果，其允许引起有差别的损耗。Since the diffracted wave has a different frequency than the incident wave, the two directions that are maximal for diffraction are not the same. Therefore, there is a nonreciprocal effect here, which allows differential losses to be induced.

当萨格奈克效应存在时，两个逆向传播的波具有相似的频率，并因此可以写成：When the Sagnac effect is present, the two counterpropagating waves have similar frequencies and can therefore be written as:

${k k}_{i i}^{+ +} \approx \approx {k k}_{i i}^{- -} &equiv; &equiv; {k k}_{i i},,$

从而上面的方程可以被写成：Thus the above equation can be written as:

$\sin (θ_{B}^{+}) - \sin (θ_{B}^{-}) \approx \frac{{k_{d}^{-}}^{2} - {k_{d}^{+}}^{2}}{2 k_{S} k_{i}}$ 方程4 $\sin (θ_{B}^{+}) - \sin (θ_{B}^{-}) \approx \frac{{k_{d}^{-}}^{2} - {k_{d}^{+}}^{2}}{2 k_{S} k_{i}}$ Equation 4

该方程可以根据声光调制器是否是各向同性的而进行不同地表达。This equation can be expressed differently depending on whether the AOM is isotropic or not.

如果声光调制器是各向同性的，具有系数n，则：If the AOM is isotropic, with coefficient n, then:

·所讨论的角度比较小；The angle in question is relatively small;

·能量的守恒给出为：The conservation of energy is given by:

其中以及k_SV_S＝ω_S即：

in And k _S V _S = ω _S namely:

其中以及k_SV_S＝ω_S即：

in And k _S V _S = ω _S namely:

·所述的频率是相似的，从而当它们的差异不出现时它们可以成为相同的。因此：• The frequencies are similar so that they can become the same when their differences do not arise. therefore:

${k k}_{d d}^{- -} \approx \approx {k k}_{d d}^{+ +} \approx \approx {k k}_{i i}^{- -} \approx \approx {k k}_{i i}^{+ +}$

因此，方程4能够被写成：Therefore, Equation 4 can be written as:

${θ θ}_{B B}^{+ +} - - {θ θ}_{B B}^{- -} \approx \approx \frac{(({k k}_{d d}^{- -} - - {k k}_{d d}^{+ +})) (({k k}_{d d}^{- -} + + {k k}_{d d}^{+ +}))}{22 {k k}_{S S} {k k}_{i i}} \approx \approx \frac{22 {k k}_{i i} (({k k}_{d d}^{- -} - - {k k}_{d d}^{+ +}))}{22 {k k}_{S S} {k k}_{i i}} = = \frac{{k k}_{d d}^{- -} - - {k k}_{d d}^{+ +}}{{k k}_{S S}}$

${θ θ}_{B B}^{+ +} - - {θ θ}_{B B}^{- -} = = \frac{22 \frac{n no}{c c} {V V}_{S S} {k k}_{S S}}{{k k}_{S S}} = = 22 n no \frac{{V V}_{S S}}{c c}$

因此，沿着传播方向、对于衍射为极大的方向之间的差异取决于声光调制器中声波的速度与光速的比率。因此：Thus, along the direction of propagation, the difference between the directions that are maximal for diffraction depends on the ratio of the speed of the sound wave to the speed of light in the AOM. therefore:

$22 {k k}_{i i}^{+ +} sin sin (({θ θ}_{B B}^{+ +})) = = \frac{(({k k}_{i i}^{+ +} - - {k k}_{d d}^{+ +})) (({k k}_{i i}^{+ +} + + {k k}_{d d}^{+ +}))}{{k k}_{S S}} + + {k k}_{S S}$

$sin sin (({θ θ}_{B B}^{+ +})) = = \frac{{k k}_{S S}}{22 {k k}_{i i}^{+ +}} + + \frac{(({k k}_{i i}^{+ +} - - {k k}_{d d}^{+ +}))}{{k k}_{S S}} = = \frac{{k k}_{S S}}{22 {k k}_{i i}^{+ +}} + + \frac{n no}{c c} {v v}_{S S} = = \frac{{k k}_{S S}}{22 {k k}_{i i}^{+ +}} + + \frac{11}{22} (({θ θ}_{B B}^{+ +} - - {θ θ}_{B B}^{- -}))$

$sin sin {θ θ}_{B B} = = \frac{{k k}_{S S}}{22 {k k}_{i i}^{+ +}} = = \frac{11}{22} (({θ θ}_{B B}^{+ +} + + {θ θ}_{B B}^{- -})),,$

和同样的。and the same.

因此，通常的布拉格入射角

对应于在θ_B ⁺和θ_B ^-之间中间位置的入射角。Therefore, the usual Bragg angle of incidence

Corresponds to an angle of incidence midway between θ _B ⁺ and θ _B ⁻ .

在各向异性的声光调制器的情况下，方程1、2和4仍然是有效的。不过，该角度不必要是较小的，并且用于能量的守恒的方程是不同的。In the case of anisotropic acousto-optic modulators, equations 1, 2 and 4 are still valid. However, the angle is not necessarily small, and the equations for the conservation of energy are different.

给出一个例子，对于普通的光学系数n_o和特别的光学系数n_e的单轴晶体，并且在声波和两个入射波沿着系数为n_e的特殊轴被偏振、以及衍射波沿着系数为n_o的普通轴被线性偏振的情况下，能量的守恒给出为：To give an example, for a uniaxial crystal with ordinary optical coefficient n _o and special optical coefficient n _e , and where the acoustic wave and the two incident waves are polarized along the special axis with coefficient n _e , and the diffracted wave is along the coefficient In the case where the ordinary axis of n _o is linearly polarized, the conservation of energy is given by:

其中

以及k_SV_S＝ω_S

in

and k _S V _S = ω _S

这会给出：This will give:

$\frac{c c}{{n no}_{o o}} {k k}_{d d}^{+ +} = = \frac{c c}{{n no}_{e e}} {k k}_{i i} - - {V V}_{S S} {k k}_{S S}$

${k k}_{d d}^{+ +} = = \frac{{n no}_{o o}}{{n no}_{e e}} {k k}_{i i} - - \frac{{n no}_{o o}}{c c} {V V}_{S S} {k k}_{S S}$

其中

以及k_SV_S＝ω_S

in

and k _S V _S = ω _S

这会给出：This will give:

$\frac{c c}{{n no}_{o o}} {k k}_{d d}^{- -} = = \frac{c c}{{n no}_{e e}} {k k}_{i i} + + {V V}_{S S} {k k}_{S S}$

${k k}_{d d}^{- -} = = \frac{{n no}_{o o}}{{n no}_{e e}} {k k}_{i i} + + \frac{{n no}_{o o}}{c c} {V V}_{S S} {k k}_{S S}$

因此，方程4可以被重写为：Therefore, Equation 4 can be rewritten as:

$sin sin (({θ θ}_{B B}^{+ +})) - - sin sin (({θ θ}_{B B}^{- -})) \approx \approx \frac{(({k k}_{d d}^{- -} - - {k k}_{d d}^{+ +})) (({k k}_{d d}^{- -} + + {k k}_{d d}^{+ +}))}{22 {k k}_{S S} {k k}_{i i}} \approx \approx \frac{22 {k k}_{i i} \frac{{n no}_{o o}}{{n no}_{e e}} (({k k}_{d d}^{- -} - - {k k}_{d d}^{+ +}))}{22 {k k}_{S S} {k k}_{i i}} = = 22 \frac{{n no}_{00}^{22}}{{n no}_{e e}} \frac{{V V}_{S S}}{c c}$

因此，声光调制器如同双折射单轴材料那样工作，对于衍射为极大的入射角是不同的，并且，其由普通的和特殊的系数决定。当在各向同性的材料的情况下，这种差异是在波的传播方向上不相同的损耗的来源。Thus, AOMs behave like birefringent uniaxial materials, for which the angle of incidence is diffractive maximally different, and which is determined by general and specific coefficients. As in the case of isotropic materials, this difference is the source of losses that are not identical in the direction of wave propagation.

只有当单一的声的声子涉及到弹性的光子/声子散射时，上面的方程才被建立，用于第一级衍射。不过，还可能使用涉及多个声子的弹性的散射建立等价方程。Only when a single acoustic phonon is involved in elastic photon/phonon scattering, the above equations are established for first order diffraction. However, it is also possible to establish equivalent equations using elastic scattering involving multiple phonons.

在各向异性的或双折射的媒介中共线的相互作用(collinearinteraction)的特殊情况下，也就是说，在不同的波矢量都具有相同方向的情况下，有可能对逆向传播的波的频率的变化进行计算。In the special case of collinear interactions in anisotropic or birefringent media, that is, where the different wave vectors all have the same direction, it is possible to change the frequency of the counterpropagating wave Changes are calculated.

给出一个例子，在各向异性的声光调制器的情况下，对于沿着作为比普通系数n_o小的系数为n_e的特殊轴被偏振的一个声波和两个入射波、以及沿着系数为n_o的普通轴被线性偏振的衍射波，于是，能量的守恒和动量的守恒给出为：To give an example, in the case of an anisotropic acousto-optic modulator, _for an acoustic wave and two incident waves polarized along a special axis with a coefficient ne smaller than the ordinary coefficient n _o , and along The ordinary axis with coefficient n _o is diffracted by the linearly polarized wave, so the conservation of energy and momentum are given as:

$\{\begin{matrix} {\overset{&RightArrow;}{k}}_{i}^{-} = {\overset{&RightArrow;}{k}}_{d}^{-} - {\overset{&RightArrow;}{k}}_{s} \\ ω_{i}^{-} = ω_{d}^{-} - ω_{s} \end{matrix}$ 其中 ${\overset{&RightArrow;}{k}}_{i}^{-} = {- k_{i}^{-} |}_{0}^{1}, {\overset{&RightArrow;}{k}}_{d}^{-} = {- k_{d}^{-} |}_{0}^{1}$ 以及 ${\overset{&RightArrow;}{k}}_{s} = {k_{s} |}_{1}^{0}$ $\{\begin{matrix} {\overset{&Right Arrow;}{k}}_{i}^{-} = {\overset{&Right Arrow;}{k}}_{d}^{-} - {\overset{&Right Arrow;}{k}}_{the s} \\ ω_{i}^{-} = ω_{d}^{-} - ω_{the s} \end{matrix}$ in ${\overset{&Right Arrow;}{k}}_{i}^{-} = {- k_{i}^{-} |}_{0}^{1}, {\overset{&Right Arrow;}{k}}_{d}^{-} = {- k_{d}^{-} |}_{0}^{1}$ as well as ${\overset{&Right Arrow;}{k}}_{the s} = {k_{the s} |}_{1}^{0}$

矢量在图3a和3b中所示出的命名系统(sentence system)中被参照。对于在相反方向上传播的波，这导致：Vectors are referenced in the sentence system shown in Figures 3a and 3b. For waves propagating in the opposite direction, this results in:

$\{\begin{matrix} k_{i}^{+} = k_{d}^{+} + k_{s} \\ \frac{c}{n_{e}} k_{i}^{+} = \frac{c}{n_{o}} k_{d}^{+} + V_{s} k_{s} \end{matrix}$ 即： $\{\begin{matrix} \frac{c}{n_{d}} k_{i}^{+} = \frac{c}{n_{o}} (k_{i}^{+} - k_{s}) + V_{s} k_{s} \\ c (\frac{1}{n_{o}} - \frac{1}{n_{e}}) k_{i}^{+} = \frac{c}{n_{o}} k_{s} (1 - n_{o} \frac{V_{s}}{c}) \end{matrix}$ $\{\begin{matrix} k_{i}^{+} = k_{d}^{+} + k_{the s} \\ \frac{c}{{no}_{e}} k_{i}^{+} = \frac{c}{{no}_{o}} k_{d}^{+} + V_{the s} k_{the s} \end{matrix}$ Right now: $\{\begin{matrix} \frac{c}{{no}_{d}} k_{i}^{+} = \frac{c}{{no}_{o}} (k_{i}^{+} - k_{the s}) + V_{the s} k_{the s} \\ c (\frac{1}{{no}_{o}} - \frac{1}{{no}_{e}}) k_{i}^{+} = \frac{c}{{no}_{o}} k_{the s} (1 - {no}_{o} \frac{V_{the s}}{c}) \end{matrix}$

$k_{i}^{+} = \frac{1 - n_{o} \frac{V_{s}}{c}}{1 - \frac{n_{o}}{n_{e}}} k_{s}$ 方程5 $k_{i}^{+} = \frac{1 - {no}_{o} \frac{V_{the s}}{c}}{1 - \frac{{no}_{o}}{{no}_{e}}} k_{thes}$ Equation 5

在相反方向上传播的波的情况给出为：The case of waves propagating in opposite directions is given by:

$\{\begin{matrix} {\overset{&RightArrow;}{k}}_{i}^{-} = {\overset{&RightArrow;}{k}}_{d}^{-} - {\overset{&RightArrow;}{k}}_{S} \\ ω_{i}^{-} = ω_{d}^{-} - ω_{S} \end{matrix}$ 其中 ${\overset{&RightArrow;}{k}}_{i}^{-} = - {k_{i}^{-} |}_{0}^{1}, {\overset{&RightArrow;}{k}}_{d}^{-} = - {k_{d}^{-} |}_{0}^{1}$ 以及 ${\overset{&RightArrow;}{k}}_{s} = {k_{s} |}_{1}^{0}$ $\{\begin{matrix} {\overset{&Right Arrow;}{k}}_{i}^{-} = {\overset{&Right Arrow;}{k}}_{d}^{-} - {\overset{&Right Arrow;}{k}}_{S} \\ ω_{i}^{-} = ω_{d}^{-} - ω_{S} \end{matrix}$ in ${\overset{&Right Arrow;}{k}}_{i}^{-} = - {k_{i}^{-} |}_{0}^{1}, {\overset{&Right Arrow;}{k}}_{d}^{-} = - {k_{d}^{-} |}_{0}^{1}$ as well as ${\overset{&Right Arrow;}{k}}_{the s} = {k_{the s} |}_{1}^{0}$

并且因此：and thus:

$\{\begin{matrix} - k_{i}^{-} = - k_{d}^{-} - k_{S} \\ \frac{c}{n_{e}} k_{i}^{-} = \frac{c}{n_{o}} k_{d}^{-} - V_{S} k_{S} \end{matrix}$ 即： $\{\begin{matrix} \frac{c}{n_{e}} k_{i}^{-} = \frac{c}{n_{o}} (k_{i}^{-} - k_{S}) - V_{S} k_{S} \\ c (\frac{1}{n_{e}} - \frac{1}{n_{o}}) k_{i}^{-} = - \frac{c}{n_{o}} k_{S} (1 + n_{o} \frac{V_{S}}{c}) \end{matrix}$ $\{\begin{matrix} - k_{i}^{-} = - k_{d}^{-} - k_{S} \\ \frac{c}{{no}_{e}} k_{i}^{-} = \frac{c}{{no}_{o}} k_{d}^{-} - V_{S} k_{S} \end{matrix}$ Right now: $\{\begin{matrix} \frac{c}{{no}_{e}} k_{i}^{-} = \frac{c}{{no}_{o}} (k_{i}^{-} - k_{S}) - V_{S} k_{S} \\ c (\frac{1}{{no}_{e}} - \frac{1}{{no}_{o}}) k_{i}^{-} = - \frac{c}{{no}_{o}} k_{S} (1 + {no}_{o} \frac{V_{S}}{c}) \end{matrix}$

$k_{i}^{-} = \frac{1 + n_{o} \frac{V_{S}}{c}}{1 - \frac{n_{o}}{n_{e}}} k_{S}$ 方程6 $k_{i}^{-} = \frac{1 + {no}_{o} \frac{V_{S}}{c}}{1 - \frac{{no}_{o}}{{no}_{e}}} k_{S}$ Equation 6

由于在两个方向上的频率是不同的，因此，这里又存在非互逆的效果。Since the frequencies in the two directions are different, there is again a non-reciprocal effect here.

对于把损耗L_d ⁺和L_d ^-作为入射角的函数的表达式，其中，入射角通过强度为I_A的声波被引入，声波在声光调制器内在长度l上与在向前(正向)方向上和在相反(负向)方向上传播的光波相互作用，该表达式通过下式给出：For the expressions for the losses L _d ⁺ and L _d ^- as a function of the angle of incidence, where the angle of incidence is introduced by an acoustic wave of intensity I _A , the sound wave is in the AOM on the internal length l with the forward (forward ) direction and light waves propagating in the opposite (negative) direction interact, this expression is given by:

${L L}^{&PlusMinus; &PlusMinus;} = = {sin sin}^{22} ((β β 11)) sin sin {c c}^{22} ((β β 11 \sqrt{11 + + {((\frac{π π}{β β {λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}))))}^{22}})) \approx \approx {β β}^{22} 11^{22} sin sin {c c}^{22} ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}))))$

这里sinc(A)是函数A的标准正弦，以及，

这里M是品质因素。因此：(其中p是光弹性系数，以及，ρ是光学相互作用材料的密度)，假设

并且声功率保持为低，这有时是希望的应用中的情况。Here sinc(A) is the standard sine of function A, and,

Here M is the quality factor. therefore: (where p is the photoelastic coefficient, and, ρ is the density of the optically interacting material), assuming

And the sound power is kept low, which is sometimes the case in desirable applications.

图4a示出了损耗L^±作为入射角θ^±的函数的一般形式。损耗对于布拉格入射角为θ_d ^±是最大的。在中间高度Δθ_1/2处的整个宽度通过下面的方程给出：Figure 4a shows the general form of the loss L ^± as a function of the angle of incidence θ ^± . The loss is greatest for ^{a Bragg angle of incidence θd±} _. The overall width at the intermediate height Δθ _1/2 is given by the following equation:

Δθ_1/2＝0.89λ_S/1Δθ _1/2 = 0.89λ _S /1

L^-具有与L⁺相同的形式，但是其在入射角的方面是偏移(offset)的。L ^- has the same form as L ⁺ , but it is offset with respect to the angle of incidence.

根据本发明的装置的工作原理基于这种效果。在给定的入射角处，在传播的光学模式的转动方向上损耗因此是不同的。通过改变入射角，损耗具有不同的改变，因此，允许模式的强度被自动控制到公共值。有可能在传播方向上产生不同的损耗，所产生的损耗越大，光学环形腔体偏移得越多。The operating principle of the device according to the invention is based on this effect. At a given angle of incidence, the loss is thus different in the direction of rotation of the propagating optical mode. By varying the angle of incidence, the loss has different changes, thus allowing the intensity of the modes to be automatically controlled to a common value. It is possible to generate different losses in the direction of propagation, the greater the resulting loss, the more the optical ring cavity is shifted.

损耗ΔL＝L⁺-L^-中的归一化差值(normalized difference)由下式给出：The normalized difference in loss ΔL = L ⁺ -L ^- is given by:

$\frac{{L L}^{+ +} - - {L L}^{- -}}{{β β}^{22} 11^{22}} = = \frac{{L L}^{+ +} - - {L L}^{- -}}{{L L}_{Max Max}} = = sin sin {c c}^{22} ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})))) - - sin sin {c c}^{22} ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{- -}))))$

由于角度θ_B ⁺和θ_B ^-接近于θ_B，所以被限制于第一阶的展开式给出为：Since the angles θ _B ⁺ and θ _B ⁻ are close to θ _B , the expansion restricted to the first order is given as:

$sin sin {c c}^{22} ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;})))) \approx \approx sin sin {c c}^{22} ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B})))) + + \frac{d d}{d d {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}} {((\frac{sin sin ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}))))}{((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}))))}))}_{{θ θ}_{B B}^{&PlusMinus; &PlusMinus;} = = {θ θ}_{B B}} (({θ θ}_{B B} - - {θ θ}_{B B}^{&PlusMinus; &PlusMinus;}))$

即： $\frac{L^{+} - L^{-}}{L_{Max}} \approx \frac{d}{d θ_{B}^{&PlusMinus;}} {(\frac{\sin (π \frac{1}{λ_{S}} (θ_{i} - θ_{B}^{&PlusMinus;}))}{(π \frac{1}{λ_{S}} (θ_{i} - θ_{B}^{&PlusMinus;}))})}_{θ_{B}^{&PlusMinus;} = θ_{B}} (θ_{B}^{-} - θ_{B}^{+})$ Right now: $\frac{L^{+} - L^{-}}{L_{Max}} \approx \frac{d}{d θ_{B}^{&PlusMinus;}} {(\frac{\sin (π \frac{1}{λ_{S}} (θ_{i} - θ_{B}^{&PlusMinus;}))}{(π \frac{1}{λ_{S}} (θ_{i} - θ_{B}^{&PlusMinus;}))})}_{θ_{B}^{&PlusMinus;} = θ_{B}} (θ_{B}^{-} - θ_{B}^{+})$

由于：because:

$\frac{d d}{d d {θ θ}_{i i}} ((\frac{sin sin ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +}))))}{π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +}))})) = = 22 π π \frac{11}{{λ λ}_{S S}} ((\frac{cos cos ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})))) sin sin ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +}))))}{π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})) {((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +}))))}^{22}})) sin sin c c ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +}))))$

$= = 22 ((cos cos ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})))) - - sin sin c c ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})))))) sin sin c c ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B}^{+ +})))) \frac{11}{{θ θ}_{i i} - - {θ θ}_{B B}^{+ +}}$

于是：then:

$\frac{ΔL Δ L}{{L L}_{Max Max}} \approx \approx 22 sin sin c c ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B})))) ((sin sin c c ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B})))) - - cos cos ((π π \frac{11}{{λ λ}_{S S}} (({θ θ}_{i i} - - {θ θ}_{B B})))))) \frac{{θ θ}_{B B}^{+ +} - - {θ θ}_{B B}^{- -}}{{θ θ}_{i i} - - {θ θ}_{B B}}$

该差异对于θ_i-θ_B＝±0.415λ_S/1是最大的，并且因此：This difference is largest for θ _i −θ _B =±0.415λ _s /1, and thus:

$\frac{ΔL ΔL}{{L L}_{Max Max}} \approx \approx 1.7 1.7 \frac{11}{{λ λ}_{S S}} (({θ θ}_{B B}^{+ +} - - {θ θ}_{B B}^{- -}))$

(W.A.Clarkson，A.B.Neilson and D.C.Hanna，“Explanation of themechanism for acousto-optically induced unidirectional operation of a ringlaser”，Opt.Lett，17，601(1992)；W.A.Clarkson，A.B.Neilson and D.C.Hanna，“Unidirectional operation of a ring laser via the acoustooptic effect”，IEEE J.Q.E 32，311(1996))。(WAClarkson, ABNeilson and DC Hanna, "Explanation of themechanism for acousto-optically induced unidirectional operation of a ringlaser", Opt. Lett, 17 , 601 (1992); WAClarkson, ABNeilson and DC Hanna, "Unidirectional operation of a ring laser via the acoustooptic effect", IEEE JQE 32 , 311(1996)).

在损耗L^±的中间高度处的整个宽度是：The overall width at the mid-height of the loss L ^± is:

Δθ_1/2＝0.89λ_S/1＝0.89V_S/1f_S Δθ _1/2 ＝0.89λ _S /1＝0.89V _S /1f _S

入射角θ_B ⁺和θ_B ^-之间的差异Δθ_B与Δθ_1/2的比率越大，系统将会越敏感。因此：The greater the ratio of the difference Δθ _B between the incident angles θ _B ⁺ and θ _B ⁻ to Δθ _1/2 , the more sensitive the system will be. therefore:

$\frac{Δ Δ {θ θ}_{B B}}{Δ Δ {θ θ}_{11 / / 22}} = = \frac{22 \frac{n no {V V}_{S S}}{c c}}{0.89 0.89 \frac{{V V}_{S S}}{11 {f f}_{S S}}} = = \frac{n no 11 {f f}_{S S}}{0.44 0.44 c c}$

最佳的声光调制器工作于最高可能的频率，并具有最大可能的相互作用长度。由于其通常呈现相当大的散射，所以，能够增大该比率的高-系数材料需根据个案而进行考虑。The optimal acousto-optic modulator operates at the highest possible frequency and has the largest possible interaction length. High-coefficient materials capable of increasing this ratio are considered on a case-by-case basis since they typically exhibit considerable scattering.

还可能通过对由压电模块产生的调制频率f进行改变而对声波的波长λ_S进行改变。通过与该频率差异成比例的数量，应用到声光调制器的压电模块的频率的变化改变了对于衍射为极大的角度。因此，对应用到声光调制器的频率进行改变与对声光调制器进行转动-衍射效率因此被改变-具有相同的效果。在这种情况下，对于给定的入射角度，损耗作为该调制频率的函数而改变，如图4b所示。因此：It is also possible to vary the wavelength λ _S of the sound wave by varying the modulation frequency f generated by the piezoelectric module. A change in frequency applied to the piezoelectric module of the acousto-optic modulator changes the angle that is maximal for diffraction by an amount proportional to this frequency difference. Therefore, changing the frequency applied to the AOM has the same effect as turning the AOM - the diffraction efficiency is thus changed. In this case, for a given angle of incidence, the loss changes as a function of this modulation frequency, as shown in Fig. 4b. therefore:

$L^{+} \approx β^{2} 1^{2} \sin c^{2} (\frac{π}{2} \frac{λ 1}{V_{S}^{2}} f_{B}^{+} (f - f_{B}^{+}))$ 以及 $L^{-} \approx β^{2} 1^{2} \sin c^{2} (\frac{π}{2} \frac{λ 1}{V_{S}^{2}} f_{B}^{-} (f - f_{B}^{-}))$ $L^{+} \approx β^{2} 1^{2} \sin c^{2} (\frac{π}{2} \frac{λ 1}{V_{S}^{2}} f_{B}^{+} (f - f_{B}^{+}))$ as well as $L^{-} \approx β^{2} 1^{2} \sin c^{2} (\frac{π}{2} \frac{λ 1}{V_{S}^{2}} f_{B}^{-} (f - f_{B}^{-}))$

其中f_B ^±对应于给出最大损耗的频率。在该频率处，声光调制器上波的入射角是布拉格入射角。where f _B ^± corresponds to the frequency giving the maximum loss. At this frequency, the angle of incidence of the wave on the AOM is the Bragg angle of incidence.

分别对应于角度范围Δθ_B和Δθ_1/2的变化(Δf_S)_B和(Δf_S)_1/2通过下面的方程被关联：The variations (Δf _S ) _B and (Δf _S ) _1/2 corresponding to the angular ranges Δθ _B and Δθ _1/2 , respectively, are related by the following equation:

$\frac{{((Δ Δ {f f}_{S S}))}_{B B}}{{((Δ Δ {f f}_{S S}))}_{11 / / 22}} = = \frac{Δ Δ {θ θ}_{B B}}{Δ Δ {θ θ}_{11 / / 22}} = = \frac{n no 11 {f f}_{S S}}{0.44 0.44 c c}$

如上所述，当声光装置被安置在两个逆向传播的波的通路上时，衍射损耗由于传播的方向而改变。为了建立用于把不同的损耗引入到两个光束的每一束中的反馈系统，这里有根据本发明使装置工作的两种可能的方法。有可能对入射角进行改变，或者对声光装置的频率进行改变。为了改变入射角，需要转动地进行自动控制的机械装置。与此相反，为了改变频率，纯粹的电子装置被使用。因此，有可能通过对两个逆向传播的光学模式的强度I⁺和I^-之间的差异具有高的灵敏度的控制电路对应用到声光调制器的频率进行控制，从而对较弱的波给予优惠(preference)，并因此获得稳定的两个方向的发射。As mentioned above, when the acousto-optic device is placed on the path of two counter-propagating waves, the diffraction loss changes due to the direction of propagation. In order to create a feedback system for introducing different losses into each of the two beams, there are two possible ways of making the device work according to the invention. It is possible to vary the angle of incidence, or to vary the frequency of the acousto-optic device. In order to change the angle of incidence, a rotationally automatically controlled mechanical device is required. In contrast, to change the frequency, purely electronic means are used. Thus, it is possible to control the frequency applied to the AOM by a control circuit with high sensitivity to the difference between the intensities I ⁺ and ^I− of the two counter-propagating optical modes, giving the weaker wave preferences, and thus obtain stable emission in both directions.

一个特别有利的情况在图5中被示出。在这种情况下，衍射图的宽度与f_B ^-和f_B ⁺之间的差异相似。对应于等于f_B的应用频率的工作点被理想地设置成：A particularly advantageous situation is shown in FIG. 5 . In this case, the width of the diffraction pattern ^is similar to the difference between _fB- and _fB ⁺ . The operating point corresponding to an applied frequency equal to _fB is ideally set to:

·损耗被最小化；以及· Losses are minimized; and

·在该点处的斜率是最大的，其使灵敏度最佳，并使系统线性化。• The slope at this point is maximum, which optimizes sensitivity and linearizes the system.

如图5所示，任何频率变化都大大增加了一个模式中的损耗，并减少了逆向传播的模式中的损耗。As shown in Figure 5, any frequency change greatly increases the loss in one mode and reduces the loss in the counterpropagating mode.

当光学环形腔体偏移得不多时，反馈机构会更加复杂以进行实施，因为它必须达到超过两个光学环形腔体中的一个的极值，以便在损耗之间获得充分的差异。超过极值使系统成为非线性的系统。When the optical ring cavities are not shifted much, the feedback mechanism is more complicated to implement, as it must reach the extremes of more than one of the two optical ring cavities in order to obtain a sufficient difference between the losses. Exceeding the extremum makes the system a nonlinear system.

应该注意到，被应用到声光调制器的信号功率是较低的，并且比需要对激光器(Q开关)进行触发、或对同相的光学模式进行阻碍的功率低得多。这种装置还具有通过更改声波的功率，能够易于对损耗的绝对值进行调节的优势。有利的是，两个逆向传播的波尽可能地靠近声波从其中被产生的声光调制器的边缘进行传递，从而减少了由于声波的传播达到光学模式而导致的延迟。It should be noted that the signal power applied to the AOM is low and much lower than that required to trigger the laser (Q-switch) or to block the optical mode in phase. This arrangement also has the advantage that the absolute value of the losses can be easily adjusted by varying the power of the acoustic wave. Advantageously, the two counter-propagating waves are delivered as close as possible to the edge of the AOM from which the acoustic waves are generated, thereby reducing delays due to propagation of the acoustic waves to the optical modes.

存在多种可能的实施例。There are many possible embodiments.

在基于频率反馈的第一个实施例中，激光陀螺仪由分散的组件构成，如图6所示。因此，光学环形腔体包括布置在环中的一套反射镜(11，12，13和14)。在图6中，反射镜被布置在矩形的四个角。当然，这种布置作为例子被给出，并且本领域技术人员已知的任何其他的布置也可能是合适的。它包括固态放大媒介19，其可以是掺杂钕的YAG晶体，或任何其他的激光媒介。它还包括声光调制器2，其由反馈装置4进行控制，并与检测器42相连。声光调制器2包括光学相互作用媒介21和压电传感器22。由传感器产生的声波可以是横向波或纵向波。两个逆向传播的光学模式5和6在光学环形腔体中传播。当激光陀螺仪转动时，它们是基于萨格奈克效应的频率偏移。这两个模式的一部分通过反射镜13被传输，并借助于半反射板43在光敏检测器3上被重组。由这种光检测器输出的信号提供了对装置的转动速度的测量。半反射板43把模式5和6的一部分传输到与反馈装置4相耦合的检测器42。由两个检测器输出的两个强度之间的差异对反馈环进行控制。声光调制器被供给其频率发生改变的信号，从而对较低强度的模式中的衍射损耗进行减少，而对较高强度的模式中的损耗进行增加。In the first embodiment based on frequency feedback, the laser gyroscope consists of discrete components, as shown in Figure 6. Thus, the optical ring cavity comprises a set of mirrors (11, 12, 13 and 14) arranged in a ring. In FIG. 6, mirrors are arranged at four corners of a rectangle. Of course, this arrangement is given as an example, and any other arrangement known to a person skilled in the art may also be suitable. It comprises a solid state amplifying medium 19, which may be a neodymium doped YAG crystal, or any other laser medium. It also includes an acousto-optic modulator 2 controlled by a feedback device 4 and connected to a detector 42 . The acousto-optic modulator 2 includes an optical interaction medium 21 and a piezoelectric sensor 22 . The acoustic waves generated by the transducer can be transverse waves or longitudinal waves. Two counterpropagating optical modes 5 and 6 propagate in the optical ring cavity. As laser gyroscopes turn, they are frequency shifted based on the Sagnac effect. A part of these two modes is transmitted through the mirror 13 and recombined on the photosensitive detector 3 by means of the semi-reflective plate 43 . The signal output by such a photodetector provides a measure of the rotational speed of the device. The semi-reflector 43 transmits a portion of the modes 5 and 6 to a detector 42 coupled to the feedback means 4 . The feedback loop is controlled by the difference between the two intensities output by the two detectors. The acousto-optic modulator is supplied with a signal whose frequency is changed such that diffraction losses are reduced in lower intensity modes and losses are increased in higher intensity modes.

在这种布置的一个可选实施例中，有利的是，安置插入在光学环形腔体中、以便对两个波的强度进行控制的多个声光调制器，如图7a和7b所示。In an alternative embodiment of this arrangement, it is advantageous to arrange a number of acousto-optic modulators inserted in the optical annular cavity for controlling the intensity of the two waves, as shown in Figures 7a and 7b.

当装置工作在高频时，这种布置是有利的。这是因为损耗随频率而增大。高于一定值，当压电块必须具有增加的小的尺寸、以便在正确的频率处产生声波时，光波和声波之间的相互作用长度1减少。声波的发散也增加，并因此对减少相互作用长度作出贡献。因此，通过增加声光调制器的数量，相互作用长度也得到增加(图7b)。This arrangement is advantageous when the device operates at high frequencies. This is because the loss increases with frequency. Above a certain value, the interaction length 1 between light and sound waves decreases as the piezoelectric mass must have an increasingly small size in order to generate sound waves at the correct frequency. The divergence of the sound waves also increases and thus contributes to reducing the interaction length. Therefore, by increasing the number of AOMs, the interaction length was also increased (Fig. 7b).

一个有利的优选实施例是这样的，在其中，两个压电块被安置在声光调制器的每个侧面，如图7a所示。可选的，压电块是偏移的，从而防止声波彼此干扰。这种几何形状的优势在于，每个声波对不同的波给出优惠。在理想的情况下，其中，声光调制器产生两个平行的声柱(acoustic columns)，将通过每个声波的功率对强度进行控制。如果声柱不是平行的，由于相互作用媒介的生产中或压电块被安装的方式中的错误，于是，每个声光调制器在不同频率处被供给信号，从而使有差别的损耗在相同或相似的声功率处是相同的。应用频率被选择成产生最佳的损耗，也就是说，第一个压电块在一个波中产生较高的损耗，而在在相反方向上传播的波中产生较低损耗，而第二个压电块具有相反的效果。因此，在每个波中的损耗被分别进行控制，反之，在只具有单一的声光调制器的装置中，同时对光波起作用是必须的。An advantageous preferred embodiment is one in which two piezoelectric masses are placed on each side of the AOM, as shown in Figure 7a. Optionally, the piezoelectric blocks are offset to prevent the sound waves from interfering with each other. The advantage of this geometry is that each sound wave favors a different wave. In an ideal situation, where the AOM produces two parallel acoustic columns, the intensity would be controlled by the power of each acoustic wave. If the acoustic columns are not parallel, due to errors in the production of the interaction medium or in the way the piezo blocks are mounted, then each AOM is fed with signals at different frequencies, resulting in differential losses at the same or similar where the sound power is the same. The frequency of application is chosen to produce optimum losses, that is, the first piezo mass produces high losses in one wave and low losses in waves propagating in the opposite direction, while the second Piezo blocks have the opposite effect. Therefore, the loss in each wave is controlled separately, whereas in a device with only a single AOM, it is necessary to act on the light waves simultaneously.

在图8所示出的第二个实施例中，由分散的组件制成的光学环形腔体被整块的光学环形腔体所替代，其由例如YAG(钇铝石榴石)晶体块进行制造。晶体的一个刻面13作为输出反射镜，而其他刻面(11，12，14)进行极好的反射，有可能对它们中的一个进行处理，从而促成光的线性偏振。声波可以在光学环形腔体的一个侧面上被直接产生，例如借助压电块22，或通过任何其他本领域技术人员已知的方法。In a second embodiment shown in Fig. 8, the optical toroidal cavity made of discrete components is replaced by a monolithic optical toroidal cavity fabricated from, for example, a block of YAG (yttrium aluminum garnet) crystal . One facet 13 of the crystal acts as an output mirror, while the other facets (11, 12, 14) reflect very well, it is possible to manipulate one of them so as to contribute to the linear polarization of the light. Acoustic waves may be generated directly on one side of the optical ring cavity, for example by means of piezoelectric blocks 22, or by any other method known to those skilled in the art.

不过，在一次完全转动中，必须在这种类型的实施例中防止波与声柱相互作用两次，因为这将抵消有差异的损耗。在这种情况下，易于看出，两个都与声柱相遇两次的波，一次在一个方向上，而第二次在另一个方向上，会经历相同的损耗，并且失去不可逆的效果。因此，例如借助于光学环形腔体内的孔或多个装置23(图8)，或借助于对声波进行吸收的任何其他装置，声波被阻碍。However, it is necessary in this type of embodiment to prevent the wave from interacting with the acoustic column twice during one full rotation, since this would cancel out the differential losses. In this case, it is easy to see that two waves that both encounter the acoustic column twice, once in one direction and a second time in the other, experience the same loss and lose the irreversible effect. Sound waves are thus blocked, for example by means of holes or means 23 (Fig. 8) in the optical annular cavity, or by any other means of absorbing sound waves.

还可能把压电块安置在光学环形腔体的一个刻面上，如图9所示。It is also possible to place the piezoelectric mass on a facet of the optical ring cavity, as shown in FIG. 9 .

这种结构的一个优势是例如通过对开发用于氦氖激光陀螺仪的多面的几何形状进行改变(adapting)，产生被称为三维激光陀螺仪的可能性，该陀螺仪对沿着三个互相垂直的轴的转动速度具有高的灵敏度。An advantage of this structure is the possibility, for example by adapting the geometry of the facets developed for HeNe laser gyroscopes, to create so-called three-dimensional laser gyroscopes, the gyroscope pair along three mutually The rotational speed of the vertical axis has high sensitivity.

Claims

1. A laser gyroscope comprising at least an optical ring cavity (1), a solid-state amplification medium (19) and a feedback system (4, 42, 43) comprising at least three mirrors (11, 12, 13), An optical ring cavity (1) and a solid-state amplification medium (19) enable two counter-propagating optical modes (5, 6) to propagate in said optical ring cavity (1) in opposite directions relative to each other , the feedback system keeps the intensity of the two counterpropagating optical modes almost the same, characterized in that the feedback system at least includes a first acousto-optic modulator in the optical ring cavity (1), the first acousto-optic modulator The transducer comprises at least one optical interaction medium (21) disposed in the path of the counterpropagating optical mode, and a piezoelectric transducer (22) generating periodic acoustic waves in the optical interaction medium.

2. Laser gyroscope according to claim 1, characterized in that the feedback system comprises electrical means for generating acoustic waves at variable frequencies depending on the strength of the two counter-propagating optical modes.

3. The laser gyroscope according to claim 1, wherein the feedback system further comprises a second acousto-optic modulator.

4. The laser gyroscope according to claim 3, wherein the first electrical means for generating the first acoustic wave controls the first acousto-optic modulator, and the electrical means for generating the second acoustic wave A second electrical device controls the second AOM.

5. The laser gyroscope of claim 4, wherein said first electrical means and said second electrical means generate different acoustic power levels.

6. The laser gyroscope according to claim 4, wherein the acoustic wave generated in the first AOM has a first frequency, and the acoustic wave generated in the second AOM has A second frequency different from the first frequency.

7. The laser gyroscope of claim 3, wherein the first AOM and the second AOM are arranged back-to-back on either side of the counterpropagating optical mode.

8. Laser gyroscope according to claim 1, characterized in that the solid-state amplification medium (19) and the optical interaction medium (21) are the same medium.

9. The laser gyroscope according to claim 8, characterized in that, the optical ring cavity (1) is a monolith, and the optical mode of being called reverse propagation and reverse propagation is only in the optical ring cavity (1) Propagates through solid material within.

10. The laser gyroscope according to claim 9, characterized in that the piezoelectric sensor is arranged on one surface of the monolithic optical ring cavity (1).

11. Laser gyroscope according to claim 10, characterized in that said surface is also used as a mirror for counter-propagating optical modes.

12. Laser gyroscope according to claim 8, characterized in that the monolithic optical ring cavity (1) comprises an attenuation for attenuating the acoustic waves so that they only interact once with the counter-propagating optical modes device.

13. The laser gyroscope according to claim 12, characterized in that the attenuation device is at least one device formed in the optical ring cavity (1), and the device is positioned in the propagation direction of the emitted acoustic wave .

14. The laser gyroscope of claim 1, wherein the laser gyroscope is three-dimensional and is sensitive to rotational speed along three mutually perpendicular axes.

15. The laser gyroscope of claim 8, wherein the laser gyroscope is three-dimensional and is sensitive to rotational speed along three mutually perpendicular axes.